1. Field of the Invention
This invention relates to a twist-wrapping machine which takes out wrapping loads, such as candies, one after another, wraps them in wrapping paper individually and twists the free ends of the wrapping paper.
2. Description of the Related Art
As a twist-wrapping machine of this type, the present applicant already proposed an innovation in Japanese Patent Application Kokai S-60-13610. This twist-wrapping machine, as shown in FIGS. 18 and 19, is a machine of the type that wrapping paper is supplied in a vertically downward direction and, in timed relation with the arrival of wrapping paper B in front of a candy A, a pusher arm 25A pushes the candy A in a horizontal direction. The machine is so designed that when the pusher arm 25A pushes the candy in a horizontal direction, fork fingers 57A and 58A of a fork hand 53A assume their "open" position in front of the candy [cf. FIG. 20(a)].
Since a push-back bar 34A preenergized to press the candy back is disposed in the center of fork fingers 57A, 58A, the candy and wrapping paper pushed out by pusher arm 25A as a unit are first held in position by the pusher arm 25A and push-back bar 34A. Then, as the fork fingers 55A, 58A are closed, the candy and paper are received by the fork hand 53A [cf. FIG. 20(b)-(d)].
However, this twist-wrapping machine has the drawback that because the candy is pushed out in a horizontal direction, it frequently happens, depending on the posture of the load, that the candy is not properly held in position by the pusher arm 25A and push-back bar 34A. Particularly when the profile of the candy is composed of curved lines, the area of contact between the candy and the pusher arm 25A and push-back bar 34A is comparatively small and, hence, the holding power, which is as much less, may result in dropping of the candy in high-speed operation.
Furthermore, since the candy pushed out is held in position by the backward pressure exerted by the push-back bar 34A, a variation in the shape and size of candy A results in changes in holding power and holding condition so that the load cannot be held in the optimal condition. Moreover, the path of movement of the push-back bar 34A is dependent on the configuration of a cam groove 51A and it is not easy to insure a complete agreement between the locus of the push-back bar 34A and that of the pusher arm 25A. For this reason, too, it was difficult to stabilize the holding condition of loads.
Under these circumstances, the conventional twist-wrapping machine cannot be operated at a sufficiently high load takeout speed and this speed is a rate-determining factor in the operating speed of the whole machine.
The object of this invention is to overcome the above-mentioned disadvantages and provide a twist-wrapping machine which is capable of providing a fast and stable load takeout action regardless of the shape of the wrapping load. In other words, the object of this invention is to provide a twist-wrapping machine capable of realizing an increased overall processing speed.